As mobile phone products move toward an era of full screens, a screen-to-body ratio of mobile phones is increasing, which brings higher requirements for hardware and structure technology. Generally, existing mobile phones set a light sensor in the top of the screen, but as a space outside the screen gets less, and the light sensor cannot be placed in the original position. Therefore, how to set the light sensor in the full screen without interference between the light sensor and the full screen has become an urgent problem to be solved.